code: def test_coefficients(self):
      with warnings.catch_warnings():
          warnings.simplefilter("ignore", RuntimeWarning)
          # 3rd order in n**(1/2)
          ne3 = ExpandedNormal([0.0, 1.0, 1.0])
          assert_allclose(ne3._coef, [1.0, 0.0, 0.0, 1.0 / 6])
  
          # 4th order in n**(1/2)
          ne4 = ExpandedNormal([0.0, 1.0, 1.0, 1.0])
          assert_allclose(
              ne4._coef,
              [1.0, 0.0, 0.0, 1.0 / 6, 1.0 / 24, 0.0, 1.0 / 72],
          )
  
          # 5th order
          ne5 = ExpandedNormal([0.0, 1.0, 1.0, 1.0, 1.0])
          assert_allclose(
              ne5._coef,
              [
                  1.0,
                  0.0,
                  0.0,
                  1.0 / 6,
                  1.0 / 24,
                  1.0 / 120,
                  1.0 / 72,
                  1.0 / 144,
                  0.0,
                  1.0 / 1296,
              ],
          )
  
          # adding trailing zeroes increases the order
          ne33 = ExpandedNormal([0.0, 1.0, 1.0, 0.0])
          assert_allclose(
              ne33._coef, [1.0, 0.0, 0.0, 1.0 / 6, 0.0, 0.0, 1.0 / 72]
          )
  
imports: import warnings
  import numpy
  from numpy.testing import assert_equal, assert_raises, assert_allclose
  import numpy.testing
  from scipy.special import gamma, factorial, factorial2
  import scipy.stats
  from statsmodels.distributions.edgeworth import _faa_di_bruno_partitions, cumulant_from_moments, ExpandedNormal
label_desc: Use image node_id 2 for calling the TestExpandedNormal obj's underlying member method code with example usage: obj.test_coefficients() without return types